This invention relates generally to systems for controlling industrial environments, and particularly to systems for controlling welding environments adjacent flammable materials and methods for concurrently conducting welding and drilling operations adjacent one another.
Drilling facilities, such as offshore platforms, are commonly constructed and maintained in remote areas of the world for use in drilling petroleum from the subterranean. Oftentimes, such drilling facilities are subjected to rigorous use as well as harsh weather conditions. Pipelines, drilling equipment, storage tanks, and decking on such facilities are routinely in need of repairs which require welding and cutting to be conducted.
In performing welding, intense heat is used to melt metals together and cause them to become integrally joined when cooled. A welding torch fueled by gas or a TIG (Tungsten Inert Gas) torch powered by a diesel or electric welding machine directs the intense heat to engage the subject metals. The force of the intense heat from a welding torch combined with the melting of metals generates sparks and slag that spray outwardly and fall downwardly from the subject metals that are being welded.
Conducting welding on petroleum drilling facilities is particularly dangerous due to the proximity of heat, sparks and slag to petroleum liquids and gases, which are flammable. Although petroleum is contained within pipelines or storage tanks, petroleum is often spilled or sprayed accidentally about a well or a drilling platform, for example, as a result of blow-out, breaches in seals, or similar conditions.
In addition to petroleum, other dangerously flammable materials exist on drilling facilities. For example, much of the heavy equipment used on a drilling platform, such as cranes, forklifts, and the like, are powered by gasoline, diesel or other fuels containing hydrocarbons that are flammable. In addition to the fuel tanks installed in such equipment, other containers for storing such fuels are often maintained on the drilling platform for re-fueling purposes.
Some safeguards have been taken to reduce the danger of igniting flammable materials on offshore platforms during welding operations. For example, drilling on offshore platforms is often ceased while welding is performed to reduce the risk of heat, sparks or slag inadvertently igniting petroleum that is being collected, processed and stored. Such cessations in drilling operations on a platform arc known in the art as xe2x80x9cshut-insxe2x80x9d. Shut-ins are intended to prevent petroleum from flowing near welding operations. However, each shut-in may cost hundreds of thousands of dollars in lost production depending upon the duration of the shut-in.
Another safeguard that has been undertaken prior to performing welding on drilling platforms is that flammable materials within containers and equipment have been isolated from the area in which welding is to be performed. Preferably, welding operations are secluded to an open space separated from pipe lines and storage containers containing petroleum as well as equipment containing flammable fuel by a distance of at least 35 feet. However, on a drilling platform, such open and secluded space is often unavailable. Occasionally, petroleum can be re-routed or otherwise moved to another location to prepare an open and secluded area for welding. However, given the limited space on offshore petroleum platforms, welding operations are commonly required to be conducted within a few feet of petroleum or other flammable materials and therefore a shut-in must be instituted.
As shown in U.S. Pat. Nos. 3,452,764 and 5,101,604, tent-like shelters have been erected about pipelines and wellheads in an effort to protect welders from inclement weather. None of these shelters however, provide for conducting welding directly adjacent flammable materials, or conducting welding on surfaces other than horizontal surfaces. Additionally, capsules, such as those shown in U.S. Pat. Nos. 3,946,571 and 5,026,219, have been made portable and have provided ventilation for welders. While such prior art capsules disclose the provision of some ventilation for welders, none of the systems associated therewith disclose controls sufficient to minimize the dangers of igniting flammable liquids and gases located adjacent welding operations so that welding and drilling operations may be performed simultaneously and adjacent one another.
It is thus seen that a need exists for a system for conducting welding adjacent flammable materials, such as petroleum and other fuels and gases, in a safe and efficient manner without shutting down drilling operations. It is to the provision of such that the present invention is particularly directed.
In a preferred form of the invention, a system for conducting welding adjacent flammable materials on a platform comprises a chamber defining an interior space. A welding apparatus is operable within the interior space. A sensor is provided for sensing combustible gas in the interior space and generating a signal. A controller is in communication with the welding apparatus and the sensor controlling the operations of the welding apparatus in response to signals received from the sensor.
In another preferred form of the invention, a method for controllably conducting welding adjacent flammable materials on a drilling platform comprises the steps of building a chamber about an object on the platform to be welded in order to separate the object from adjacent flammable materials and to create a substantially sealed environment about the object, blowing air into the chamber to create a positive pressure within the chamber that inhibits combustible gases from entering the chamber, operating a welding torch within the chamber to repair the object while sensing inside the chamber for the presence of combustible gas above a pre-selected level, and ceasing the welding operations upon the sensing detecting combustible gas inside the chamber above the pre-selected level.